This invention relates to the generation of aspherical surfaces of revolution.
Aspherical surfaces of revolution are conventionally produced by numerically controlled machines or by correction of spherical surfaces through use of lapping and polishing techniques. For instance, it is customary to produce a spherical surface which approximates a desired aspherical surface, and then systematically to remove or add material until the desired asphericity is obtained. The initial spherical surface may be produced by the well-known chordal generator with which one cuts the spherical surface by rotating a workpiece about one axis against a tool tip being rotated about a second axis normal to and intersecting the first axis. The spherical radius is equal to the distance of the tool tip from its center of rotation.